I am the mother of twins girls and they have baby daughters 2 months apart in age. When they bring them to visit it is like seeing and experiencing them all over again, as they both look and behave like their mums did. Suprisingly they are both second children and their older brother and sister are both completely different in all ways. I also had a son 21 months after the girls and when they all arrive at the same time, with six grandchildren, I feel the same buzz as I did when looking after the three of them when they were small.
I have a cupboard full of toys, books, jigsaws,games, colouring books, etc. so that they are never bored when they visit. I also have nursery rhyme songs that we sing and dance to. It can all be packed away when they are gone, but I want it to be fun when they are here.